python - pandas fillna not working

Question

I have a dataframe with nans in it:

>>>df.head()
Out[1]: 
            JPM US SMALLER COMPANIES C ACC
1990-01-02                             NaN
1990-01-03                             NaN
1990-01-04                             NaN
1990-01-05                             NaN
1990-01-08                             NaN

I have another dataframe with values in it:

>>>t.head()
Out[1]: 
1990-01-02    51.95
1990-01-03    52.63
1990-01-04    53.04
1990-01-05    52.07
1990-01-08    51.73
Name: JPM US SMALLER COMPANIES C ACC, dtype: float64

Unfortunately, df.fillna does not appear to be working for me:

>>>df.fillna( t ).head()
Out[1]: 
            JPM US SMALLER COMPANIES C ACC
1990-01-02                             NaN
1990-01-03                             NaN
1990-01-04                             NaN
1990-01-05                             NaN
1990-01-08                             NaN

[5 rows x 1 columns]

Why is this happening? I am on pandas 0.13.1

Answer 1

you need inplace

df[1].fillna(0, inplace=True)